Some of the richest people in the world - Elon Musk, Jeff Bezos, and Mark Zuckerberg - made their fortunes in Silicon Valley. However, a new report in the Wall Street Journal suggests that most U.S. billionaires did not amass their wealth in tech. Instead, it's the banking and finance fields that have produced most of the country's super-rich. According to data shared with the WSJ from wealth intelligence company Altrata, there were 1,135 billionaires in the U.S. last year, up from 927 in 2020.